Cylinder crosshatch general purpose vs. race

[statsystems]

For the most part I use 70 grit stones until I am .003" to final size then I switch to 220 grit stones until .0005 to final size then I switch to 280 grit stones. After reaching final size I check back every few hours and recheck the bore sizes. I like to leave it sit overnight and recheck in the morning. I have experimented with IR thermometers and found some interesting results. You can measure the cylinders of the block with a temperature at 70 degrees hours after you've last honed the block and come back the next day and check the block at the same 70 degrees and have it shrink by .0002"-.0003". After I am satisfied that the block is done shrinking then I install the honing brushes and make just two strokes up and down with light pressure.

That's a good standard.

I have a slightly different take on it. Mostly 220 is my base finish, so I set the size in this step. So I hone basically to indicated size(measured hot, so probably .0005 short), then let it sit, then come back later and hone some more as needed, so I essentially finish the cylinder to the base finish being .0002-.0005 short of my actual target size (depending on what follows).
THEN, when I am satisfied with it, I hone a --limited number of strokes-- of 280 and/or 400 and/or a brush (depending on app) and then it's done. If it ends up a few tenths smaller than I wanted I am NOT going to go back and hone any more, if it's one or two tenths over..... too bad, it's done. Not sure if there is a name for that.

Plenty good enough for 99.2% of most engines built?

[modok]

I'm not sure if you got the point. I'd say I'm applying it all the time when most are only doing that sometimes.
The variability is due to having to guess how many strokes for the finish and how much that will take out of a base finish of ? RA, which does vary a small amount, sometimes from one side of the block to the other If I did the same engine all the time I could tune it in better, but often each day is different boulder to push around.

lets say polishing a crank.
You grind it true and to size slightly over, THEN polish. You have to guess how much to leave to polish off. Polishing more or less to try to get the size right is WRONG, as under polishing it's not smooth, or over polishing it will become less true.

lets say you are block sanding a car.....
You get it straight in the coarse steps, then all the finer steps are just removing the scratches.

Same thing.

You can switch to a finer grit too soon and make up for it, but it's usually A LOT BETTER to avoid that.
it's not really a advanced concept, but it took.....longer than I'd like to admit....before I really GOT it. I wish I had figured that out sooner.

[MotionMachine]

I have a lot of experience with a profilometer, I use it all the time. But only since I bought a diamond hone so I can't comment on results for vitrified stones except for one quick test I did for a friend. I still have a Serv-Equip AN oil based hone. I did a quick hone on a SBC of 220/280, then one with 220/280/plateau brush. I don't remember the numbers I got but the first bore was near perfect and the second was perfect. I was surprised at how easily I arrived at those results, not so easy with diamonds. Every block is different so I keep a log of what method I used so I have it for the next one. And I have the opposite problem that most have, I have to allow for the block to warm back up. A block will actually grow a couple tenths if the shop isn't warm. So now I leave the heat on 24/7, for the hone and the CNC so that everything is at temp. Especially critical for aluminum.

[statsystems]

I have a lot of experience with a profilometer, I use it all the time. But only since I bought a diamond hone so I can't comment on results for vitrified stones except for one quick test I did for a friend. I still have a Serv-Equip AN oil based hone. I did a quick hone on a SBC of 220/280, then one with 220/280/plateau brush. I don't remember the numbers I got but the first bore was near perfect and the second was perfect. I was surprised at how easily I arrived at those results, not so easy with diamonds. Every block is different so I keep a log of what method I used so I have it for the next one. And I have the opposite problem that most have, I have to allow for the block to warm back up. A block will actually grow a couple tenths if the shop isn't warm. So now I leave the heat on 24/7, for the hone and the CNC so that everything is at temp. Especially critical for aluminum.

The switch from vitrified to diamond abrasives was difficult for me. Bore geometry was just as good or better with the diamond hone but it took me a while to get the finish where is was as good as vitrified abrasives.

[David Redszus]

You grind it true and to size slightly over, THEN polish. You have to guess how much to leave to polish off. Polishing more or less to try to get the size right is WRONG, as under polishing it's not smooth, or over polishing it will become less true.

If you know the Ra number of the rough hone surface and the Ra number of the desired final honed surface, the amount of stock removal can be easily calculated.

[createaaron]

Just what purpose does the brush serve that a 400 grit stone does not?

Does anyone have some actual surface profilometer data or are we just talking?

The idea being the brushes is that it removes the material that's been folded over into the valleys of the crosshatch. From what I've found, the bore looks so much cleaner after using brushes. Becomes more of that white color I want.

[createaaron]

For the most part I use 70 grit stones until I am .003" to final size then I switch to 220 grit stones until .0005 to final size then I switch to 280 grit stones. After reaching final size I check back every few hours and recheck the bore sizes. I like to leave it sit overnight and recheck in the morning. I have experimented with IR thermometers and found some interesting results. You can measure the cylinders of the block with a temperature at 70 degrees hours after you've last honed the block and come back the next day and check the block at the same 70 degrees and have it shrink by .0002"-.0003". After I am satisfied that the block is done shrinking then I install the honing brushes and make just two strokes up and down with light pressure.

This is almost exactly what I as well. On my first cylinder I will hone around .001" short and finish it. Use the profilometer and log my values. Decide if i like them then repeat my finishing step on the rest of the cylinders. I normally go from 120 to 220, then ball hone and brush. Im going to try finishing with a few strokes of 400 stones then brush/ no brush as well.

[David Redszus]

Just what purpose does the brush serve that a 400 grit stone does not?

Does anyone have some actual surface profilometer data or are we just talking?

The idea being the brushes is that it removes the material that's been folded over into the valleys of the crosshatch. From what I've found, the bore looks so much cleaner after using brushes. Becomes more of that white color I want.

What is the grit number of brushes? What surface finish Ra numbers do they produce? What is the abrasive material?
I have never, ever, seen a brush produce as clean a finish as that produced by a ball hone. Do brush manufacturers publish surface finish data?

[statsystems]

For the most part I use 70 grit stones until I am .003" to final size then I switch to 220 grit stones until .0005 to final size then I switch to 280 grit stones. After reaching final size I check back every few hours and recheck the bore sizes. I like to leave it sit overnight and recheck in the morning. I have experimented with IR thermometers and found some interesting results. You can measure the cylinders of the block with a temperature at 70 degrees hours after you've last honed the block and come back the next day and check the block at the same 70 degrees and have it shrink by .0002"-.0003". After I am satisfied that the block is done shrinking then I install the honing brushes and make just two strokes up and down with light pressure.

This is almost exactly what I as well. On my first cylinder I will hone around .001" short and finish it. Use the profilometer and log my values. Decide if i like them then repeat my finishing step on the rest of the cylinders. I normally go from 120 to 220, then ball hone and brush. Im going to try finishing with a few strokes of 400 stones then brush/ no brush as well.

You need to be careful with a 400/brush finish. The customer needs to be able to not was the cylinders down. I've only done it to a few alcohol engines (most were mine) and it was easy to get oil by the rings if you weren't damn careful.

[statsystems]

Just what purpose does the brush serve that a 400 grit stone does not?

Does anyone have some actual surface profilometer data or are we just talking?

The idea being the brushes is that it removes the material that's been folded over into the valleys of the crosshatch. From what I've found, the bore looks so much cleaner after using brushes. Becomes more of that white color I want.

What is the grit number of brushes? What surface finish Ra numbers do they produce? What is the abrasive material?
I have never, ever, seen a brush produce as clean a finish as that produced by a ball hone. Do brush manufacturers publish surface finish data?

David I don't who makes the brushes I used but they were the segmented ones that Yunick developed with PMT and they were not like the BR types.

Damn I wish I had my notes. Sealed Power did a bunch of the research for me, through the guy (whose name I can't recall but in the articles in Circle Track the guy at PMT was who helped me get help from SP and it pisses me off I can't remember his name any more) at PMT. Then the guy who was reaping for SP hooked me other with some other people who furthered my study.

All that stuff is either sitting in some guys house, in a warehouse or gone.

[4sfed]

I have experimented with IR thermometers and found some interesting results. You can measure the cylinders of the block with a temperature at 70 degrees hours after you've last honed the block and come back the next day and check the block at the same 70 degrees and have it shrink by .0002"-.0003".

You're only measuring surface temperature with IR. I suspect the core takes longer to cool than you think.

[createaaron]

You need to be careful with a 400/brush finish. The customer needs to be able to not was the cylinders down. I've only done it to a few alcohol engines (most were mine) and it was easy to get oil by the rings if you weren't damn careful.

Do you reccomend just a 400 finish then just use the nylon type brush when im cleaning?

[createaaron]

What is the grit number of brushes? What surface finish Ra numbers do they produce? What is the abrasive material?
I have never, ever, seen a brush produce as clean a finish as that produced by a ball hone. Do brush manufacturers publish surface finish data?

That i could not tell you.. i just use whats available at school. Probably 300 range.. We normally dont measure RA, seems obsolete as far as surface finish. I normally use a ball hone then brush, and it produces a very very clean bore.

[David Redszus]

We normally dont measure RA, seems obsolete as far as surface finish.

Ra is not a real measurement; it is a computed value based on the average height of the peaks and the average depth of the valleys. These two are usually identical when a single grit abrasive is used. It cannot be used when subsequent honing steps are involved. A plateau finish cannot be measured using Ra values. We do not know what surface finish the plateaus will have.

If we take a junk cylinder and hone (for a lengthy period to eliminate deep scratches), using a 400 grit abrasive, we can then use Ra to determine what surface finish will be produced across the flats of the plateaued surface.

I normally use a ball hone then brush, and it produces a very very clean bore.

A ball hone is an excellent tool for a final finish. No brush hone is necessary or useful, except for a scrub brush with soap and water to clean the deep grooves. When completed, a clean oiled cloth will remain clean when applied to the cylinder walls.

The term "plateaued" finish is often misunderstood. It represents the area of the plateau tops divided by the total honed surface area. It is the wall area that will be in contact with the ring. Since we are cutting off the triangular peaks of a rough honed surface, the more we remove, the greater the surface area. For normal work, a ratio of 70%-75% is targeted. If the ring loading is excessively high, a higher ratio of 80%-85%, is targeted. A 70% ratio will last longer, have less friction, and have more oil reserve. A 85% ratio will provide better short term sealing. When the ratio approaches 100% there are no more deep scratches remaining to carry oil on the wall surface.

[modok]

No brush hone is necessary or useful, except for a scrub brush with soap and water to clean the deep grooves.

I agree with all else, however, do you think Sunnen is wrong?
http://www.sunnen.com/ProductDetails.as ... &NavID=694

darton seems to think it's ok
http://www.darton-international.com/pdf/sunnen.pdf

CP thinks it's ok
http://www.google.com/url?sa=t&rct=j&q= ... dtCF7SYa9w